Schema extensions utility?

[greyexpert]

Hello there,

Do you have any plans of porting extendSchema utility from graphql-js?
https://github.com/graphql/graphql-js/blob/master/src/utilities/extendSchema.js

It would be great to have ability to build modular schema and to extend type definitions using

extend type TypeName {}

[vladar]

That would be nice, but it's unlikely we'll port it soon (too little time now). So PRs are welcome!

[crirus]

Hello guys,

I already have the code ported along with a merging/stitching function taken from Apollo. It's not 100 percent as they keep pushing more features but I can drop it on a repository so you can play with it and maybe help polishing the code

[greyexpert]

It work this way in graphql-js at the moment:

The extend type statement is not processed when you build schema in graphql-js using buildASTSchema. The statement is processed only in extendSchema which accepts already built root schema and applies extensions to it.

What do you think, if we follow a slightly different approach:

We can add the support of extensions into BuildSchema itself without adding an extra utility like ExtendSchema. Having this feature supported, we will be able to build modular schema by just concatinating multiple schemas before passing them into BuildSchema::build

For example:

RootSchema.graphqls

schema {
  query: Query
}

type Query {
  version: String
}

UsersSchema.graphqls

type User {
  name: String
}

extend type Query {
  users: [User]
}

Then, all we need is to concatenate them into result schema and pass to BuildSchema::build

$schemaSources = [
    file_get_contents("RootSchema.graphqls"),
    file_get_contents("UsersSchema.graphqls")
];
        
$schema = BuildSchema::build(implode("\n\n", $schemaSources));

This feature will require less time, comparing to developing new utility. Also there are a lot of useful private methods in BuildSchema class, which can be re-used.

And, yes, I can create a pull request, if you guys don't mind this feature?

Related discussion in graphql-js repo:
graphql/graphql-js#922

[greyexpert]

@crirus
It would be great if you share your implementation

[crirus]

@greyexpert here is the initial code, any questions let me know
https://github.com/crirus/graphql-php-tools

[vladar]

It has been ported into https://github.com/webonyx/graphql-php/blob/master/src/Utils/SchemaExtender.php

[MidnightDesign]

@vladar I'm sorry but I don't really get it. How is it supposed to be used? The class isn't referenced anywhere in the code and it has no public methods. Is it supposed to be extended? If so, why isn't it abstract and how is the inheriting class supposed to be used?

Edit: I'm an idiot. I didn't see the extend() method down there.

[MidnightDesign]

@vladar I'm sorry if this is a dumb question, but is this supposed to somehow combine the two schema files

type Person {
    name: String!
}

type Person {
    age: Int!
}

into one

type Person {
    name: String!
    age: Int!
}

Because that's exactly what I would need.

[vladar]

@Torsten85 Can you please clarify as you are the one ported this utility?

[Torsten85]

it should be used exactly like the graphql-js counterpart (https://github.com/graphql/graphql-js/blob/master/src/utilities/extendSchema.js#L103).

Small example:

$sdl = '
  type Query {
    defaultValue: String
  }
';

$documentNode = \GraphQL\Language\Parser::parse($sdl);
$schema = \GraphQL\Utils\BuildSchema::build($documentNode);

$extensionSdl = '
  extend type Query {
    extendendValue: String
  }
';

$extendedDocumentNode = \GraphQL\Language\Parser::parse($extensionSdl);
$extendedScheam = \GraphQL\Utils\SchemaExtender::extend($schema, $extendedDocumentNode);

echo \GraphQL\Utils\SchemaPrinter::doPrint($extendedScheam);

this will echo:

type Query {
  defaultValue: String
  extendendValue: String
}

[MidnightDesign]

@Torsten85

Is the following supposed to work?

$sdl = '
  type Query {
    defaultValue: String
  }
  type Foo {
    value: Int
  }
';

$documentNode = \GraphQL\Language\Parser::parse($sdl);
$schema = \GraphQL\Utils\BuildSchema::build($documentNode);

$extensionSdl = '
  type Bar {
    foo: Foo
  }
';

$extendedDocumentNode = \GraphQL\Language\Parser::parse($extensionSdl);
$extendedScheam = \GraphQL\Utils\SchemaExtender::extend($schema, $extendedDocumentNode);

echo \GraphQL\Utils\SchemaPrinter::doPrint($extendedScheam);

I get a Uncaught Type "Bar" not found in document.. Obviously, this is because the extension schema references a type from the base schema, but what is this feature for if not for this use case?

[Torsten85]

@MidnightDesign you are completely right, this should work! (https://codesandbox.io/s/yjmpnop8k9) I've digged a little deeper and found a "bug" in my implementation. This PR should fix this: #417